A wide variety of decorative lights are currently available, among which the lamp strings simply assembled for decorating front doors of the bars and/or restaurants are most commonly used. In some cases, tube lamps arranged on a roof give out magic run-after lighting effects for decorating environments. Being short of variations in the tube lamp category, people often strength the decorative effects by changing the winding shapes of the tube lamps. However, these changes are not easy to produce a wonderful visual effect. In general, illuminating lamps disposed on a garden lawn for decorative purposes are structurally complicated and manufacturally expensive and unable to display a decorative effect that two-row lights run after simultaneously.